How can I tell if my two young male rats are playing with me?

I have had two fairly young male rats for about 2 weeks now. Each day I let them run around in the spare room to have a play. Sometimes I lay down on the floor and they crawl all over me and gently nibble on my fingers. When I move my hands around to play with them they sort of buck and bounce around me in big leaps and come and jump on me again. Are they playing with me? Sometimes they both will roll around on the floor and try to jump on each other.How can I tell if my two young male rats are playing with me?
Yes they are playing. Rats play like kittens and puppies. I had a rat that liked his neck scratched and he would try to groom me also by licking and nibbling gently on my fingers. They are the best small animal pets because they seek out your company and my rat wouldn't run away either.How can I tell if my two young male rats are playing with me?
Sounds like a combination of curiosity and play to me :-) All rodents are extremely nosy.